Repeating air gun



Se t. 11, 1956 E. E. FOSTER REPEATING AIR GUN Filed March 25, 1953 INVENTOR. dzmiffim MIN. N N

ATTORNEYS.

MN mN United States REPEAT-ENG GUN Edwin E. Foster, Austin, Tex. Application March 23, 1953, Serial No. 343,835 9-,Claims. (Cl. 124-123) This invention relates to repeating air guns and more particularly, to guns of the type'which shoot light projectiles such as Ping-pong balls.

Repeating air guns have been proposed in which a series of projectiles are propelled successivelytfrom the gun barrel past a yielding resistance at the discharge or muzzle end of the barrel by pumping air into the rear end of the barrel. One difliculty encountered in such guns is that a plurality of projectiles tend to be discharged each time the pump is operated with the result that the projectiles are not properly propelled from the barrel with the desired accompanying noise and. the number of shots for each loading is reduced.

It is one of the objects of the presentinvention to provide a repeating air gun in which projectiles are discharged singly from the gun in response to air pumped into the rear end of the barrel.

Another object is to provide a gun in which the 'discharge of each projectile is accompanied by a sharp popping sound which is very pleasing to users of the gun.

.Still anotherobject is to provide a gun in whichdischarge of the projectiles is yieldingly resisted by an elastic sleeve fitted. over the end. of the barrel and infiated by air pressure acting on the outermost projectile.

It has been found, according to the present invention,

that such a sleeve functions to insure discharged the projectiles singly, and further, that it increases the sharpness and intensity of the popping sound accompanying discharge of the projectiles, over the types of restrictions heretofore used.

A still'further object of the invention is to provide a gunin which-the discharge resistance sleeve can easily befolded out of the way so that projectilescan be loaded through the muzzle end. of the barrel.

A further object is to provide a..gun inwhich theprojectiles are advanced tofiring position by thesame-air I pressure which effects the discharge.

According to one feature of the invention, .a follower is provided in the barrel behind the projectiles forjrlight frictional engagement in the barrel to remain in position ,under ordinary handling of the gun and which is formed 'forrestrieted flow of air therepast for discharge ofthe projectiles. It has'been found that such afollower will be held by thefiring restriction after all of the projectiles'have been discharged from the gun since air will flow therepast at a sufficiently rapid rate to prevent ,dis-

charge of the follower. It is further contemplated that an audible signal may beprovided on the followento indicateto the user when the gun is empty.

Further-objects and features relate to the Construction of the gun and the mounting of the pump and its operating handle therein in a very simple and inexpensive manner to provide adequate guidance and support for the pump operating handle.

The above and otherobjects and features of the in- :vention will be more readily apparent'from the following description when read in'connection with the accompanyingdrawing in which Figure 1 is a longitudinal central section through a gun embodying the invention with parts in elevation;

Figure 2 is a partial section showing the condition of the discharge sleeve during firing;

Figure 3 is a similar view showing the condition of the discharge sleeve during loading;

Figure 4 is a sectional view illustrating the discharge sleeve as molded;

Figure 5 is a section showing the discharge sleeve as invertedfor mounting on the gun;

Figures 6 and 7 are sections through alternative follower constructions;

Figure 8 is a section through the rear end of the gun stock on the line 8-,-8 of Figure 1; and

Figure 9 is a view partially in elevation and partially in section of still another follower construction.

The gun, as shown, comprises an elongated tubular barrel 10'which may be formed of metal orof a plastic tubeif desired, and which is relatively rigid. The rear end of the barrel is closed by a cap 11 and is supported in a stockindicated generally at 12 which is preferably formedof a pair of plastic molded halves secured togetheralong a central vertical plane. The stock includes a forward socket'portion 13 into which the rear end of the barrel is received to support the barrel and a hollow rear portion 14 in which a pump may be mounted.

The pump may be any very simple and inexpensive type of cylinder and piston pump such as commonly used oninsecticide sprays and the like. As shown, the pump includes a cylinder 15 which fits into thehollow Stock near the rear end thereof. For this purpose the stock -may be formed with a forward web 16 against which the front end of the cylinder 15 fits and a rear socket portion 17 molded integrally with the stock halves to receive and hold the rear end of the pump cylinder. In this way the pump may be very simply mounted without requiring external fastenings and will be firmlysupported in the stock. A piston 18 is slidable in the cylinder 15 and carriesthe usual cup'washer which will seal against the the operator and reciprocated parallel to the barrel to ,op-

crate the gun. It will be seen that with this construction the piston rod is supported for sliding movement by the :pump barrel itself, by the flange 16 and by the fo1ward socket portion of the stock 13 -so that no additional supporting connections for the handle are required.

The rear end of the pump cylinder is connected by a tube 22 extending through the hollow stock with the rear end of the barrel 10. For this purpose the closure 11 is formed with a central opening to receive an elastic sleeve 23 having a tubular bore through most of its length but terminating in a closed forward end having a narrow slit therein. The forward end of the tube 22 is inserted in the sleeve23 to-press the sides thereof against the sides of =t-he opening in the closure 11 and hold place. Under normal conditions, the sleeve 23 will be closed, but when air pressure is exerted the sleeve firmly in forward end of the through the tube 22 the forward end of the sleeve will expand allowing the slit to open so that air can flow into .the barrel. When-the piston 18 is moved forward the forward end of the sleeve will close to prevent sucking air from'the' barrel into the pump so that the sleeve serves 'notonly as a connector element but also as a check valve.

The barrel is adapted to hold a series of projectiles, shown as spherical balls 24, which are preferably light hollow balls similar to conventional Ping-pong balls. Discharge of the balls from the barrel is restricted by a firing restrictor sleeve which includes a relatively thick rear ring portion 25, a relatively thick forward ring portion 26, and a thin inflatable sleeve portion 27. The firing restrictor sleeve is preferably molded of an elastic material such as rubber and is preferably molded in a position inverted in respect to its operating position, as shown in Figure 4. As best seen in this figure, the thin sleeve portion 27 connects to the inner edge portions of the rings 25 and 26 and may be radially reinforced by annular thicker beads 28. The outer edge of the ring portion 26 may be similarly reinforced by an annular head 29. For use, the sleeve is inverted or turned inside out as indicated in Figure 5 so that the sleeve portion 27 connects to the outer edges of the rings 25 and 26 and the reinforcing beads are on the outside. In this condition the sleeve is slipped over the end of the barrel with the ring 25 fitting over'an annular flange 31 secured to the barrel as by having a press fit therewith.

The sleeve is of such an initial diameter that the ring 25 willhave a tight stretched fit against the barrel and will secure the rear end of the sleeve to the barrel at a point spaced rearwardly from the front end of the barrel. The sleeve portion 27 is slightly stretched to press against the outside of the barrel and the ring 26 lies beyond the end of the barrel and extends radially inward to present an opening of normally smaller diameter than the projectiles. The ring 26 may be tapered as shown and preferably lies close to the end of the barrel with a relatively small clearance so that it can easily be folded for loading the gun as described hereinafter.

When air pressure is exerted on the projectiles in the barrel, which preferably fit loosely in the barrel so that air can leak past them, the parts will assume the condition illustrated in Figure 2. Under these conditions air pressure acts on the outermost projectile and also leaks past this projectile to inflate the sleeve portion 27 radially and to stretch it axially. As the pressure increases it will eventually build up to a value suflicien-t to stretch the ring 26 so that the projectile can pass through it and be propelled from the gun with a relatively high degree of pressure depending upon the restriction of the ring 26. Since there is pressure throughout the entire barrel, there is a tendency for more than one of the projectiles in the barrel to be discharged past the restriction. It has been found, however, that with the present construction this tendency is overcome so that the projectiles are discharged singly. While the exact reasons for this are not completely understood, it is believed that this action is due to the fact that when the outermost projectile is dis charged and air pressure is relieved, the air contained in the inflated sleeve portion 27 flows around the front end of the barrel and tends to hold back the second projectile of the series which is still within the barrel, as shown in Figure 2. In any event, repeated tests have indicated that only one projectile will be discharged at a time so that it will be properly fired and so that the desired noise will accompany the discharge of each projectile.

In connection with the noise, it has further been found that the present construction provides a much sharper and louder popping noise than that produced by restrictions of the type heretofore used. This is believed to be due partially to the fact that the inflated sleeve portion 27 acts similar to a conventional toy balloon in many respects and creates the same type of popping noise as that which occurs when an inflated toy balloon bursts. Additionally, a portion of the improved popping noise may be due to physical slapping of the sleeve portion 27 against the end of the barrel as the sleeve portion is suddenly deflated.

In loading the gun, the projectiles are inserted through the muzzle end thereof and for this purpose the ring 26 is preferably folded back over the sleeve portion 27 and over the end of the barrel, as shown in Figure 3. To facilitate this folding, it is preferred to mount the discharge sleeve so that the rear edge of the ring 26 lies closely adjacent to the end of the barrel, as described above. Folding is further facilitated by molding the sleeve in an inside out condition and reversing it before it is mounted so that the sleeve has a natural tendency to invert. It has been found that when the ring is constructed as disclosed and mounted on a gun barrel, the outer discharge ring 26 can very easily be folded back on the sleeve portion 27 as shown in Figure 3 so that a series of projectiles can easily be inserted through the open muzzle end of the barrel. Upon completion of the loading operation, the ring 26 can easily be flipped back to operating position as shown in Figures 1 and 2 for firing of the gun.

Projectiles are advanced through the barrel toward the muzzle end thereof by a follower fitting slidably in the barrel behind the projectiles. As shown in Figure l, the follower comprises a generally cup-shaped plastic member 32 having a plurality of ribs thereon to fit against the sides of the barrel and guide the follower and having a recess in its forward end into which the rearmost projectile may fit. It is intended that there shall be a restricted leakage of air past the follower for which purpose the ribs may provide a slight clearance around the rear skirt portion of the follower or additionally, the follower may be perforated, as indicated at 33. The follower preferably has a light frictional fit in the barrel so that it will stay in position under normal handling of the gun, but will easily be advanced by air pressure and can easily be forced backward in the barrel by the projectiles during loading.

In operation of the gun, assuming that it is loaded with balls as shown in Figure l, the pump handle 21 is pulled forward so that air in the front end of the pump cylinder will flow past the piston 18. When the pump handle is pulled backward the air will be pumped through the tube 22, past the check valve sleeve 23, into the rear end of the barrel back of the follower. This will cause the follower to advance until the projectiles reach the position shown in Figure 1 with the outermost projectile engaging the restricting ring 26. Air will then leak past or through the follower and around the rearmost projectiles in the barrel to exertpressure on the forward projectile and expand .the firing sleeve, as shown in Figure 2. When the pressure reaches a sufiicient value, which will normally be accomplished once for each stroke of the pump, the outermost projectile will be discharged as described above'and pressure in the barrel will be relieved. 0n the next operation of the pump, the projectile and follower Will again be advanced and the outermost projectile will be-fired inthe same manner. This will continue until all of the projectiles have been discharged, at which time the follower will have reached the outer end of the barrel and engaged the restricting ring 26. It hasbeen found that due to leakage of air past the follower, sufficient pressure cannot be built up to force it past the restricting ring so that it will simply remain in the outer position in the barrel regardless of operation of the pump until the gun is again loaded.

Advantage may be taken of the air flow past the follower when it is in its outermost position to produce an audible signal. For this purpose the follower may be modified as shown in Figure 6 to include a central tubular neck portion 34 into which a vibrating reed unit 35 is inserted. With projectiles in the barrel, the flow of air past the follower will be at such a low rate that the reed unit will-not be operated. However, when the follower is in the outer end of the barrel with no projectiles ahead of it, operation of the pump will cause a flow of air through the reed unit sufficient to operate it and to producean audible signal indicating that the gun is empty.

'housing 37 may be secured thereto withamalignedopening 38 therein to form a whistle. FlOW'Qf lair through the openings 36 and 38 is at too low aratev to produce an audible signal when there are projectiles inthebarrel, but when the barrel is empty, air pumped through these openings will produce a whistlingsoundto indicate that the gun is empty.

Figure 9 illustrates an alternative form of follower which is extremely simple and inexpensive. As .shown in mis figure, the follower comprises a ball formed ,of a porous resilient material such as sponge rubber and )of a size'to fit into the barrel witha light frictional fit.

When such a ball is used, air will leak through it at a suflicient rate to produce the .desired feeding and'firing operations when there are projectiles in the barrel. When the barrel isempty, the follower will be held by the ling 26 and air will leak through it at a high enough rate to prevent build-up of a sufiicient pressure-to force 'the follower from the barrel.

of the barrel, the sleeve being restricted beyond the end of the barrel to engage and seal against a projectile, means to secure the sleeve to the barrel at a point spaced from the end of the barrel, the projecting end of the sleeve being thicker than the adjacent part thereof and being foldable over the adjacent part and over the barrel for loading of projectiles through the discharge end of the barrel, a follower fitting slidably in the barrel with sufficient frictional force to remain in its existing position under normal handling of the gun and formed for restricted flow of air therepast, and means to force air under pressure into the barrel to the rear of the follower.

2. A repeating air gun comprising a rigid tubular barrel adapted to hold a series of projectiles which fit loosely in the barrel, a resilient sleeve fitting over the discharge end of the barrel and projecting beyond the discharge end of the barrel, the sleeve being restricted beyond the end of the barrel to engage and seal against a projectile, means to secure the sleeve to the barrel at a point spaced from the end of the barrel, a follower fitting slidably in the barrel to the rear of the projectiles and having a restricted air passage therethrough, audible signal means carried by the follower to be actuated by flow of air in excess of a predetermined minimum required to force projectiles from the barrel through said passage, and means to force air under pressure into the barrel to the rear of the follower, the signal means being operated by flow of air through said passage after all of the projectiles have been forced from the barrel.

3. A repeating air gun comprising a rigid tubular barrel adapted to hold a series of projectiles, a hollow stock secured to the rear end of the barrel, a pump cylinder in the stock to the rear of the barrel, a piston in the cylinder, a piston rod connected to the piston extending slidably through and guided by the stock below the barrel, a handle secured to the forward end of the piston rod and underlying the barrel, a closure for the rear end of the barrel formed with an opening therethrough, an elastic sleeve extending through the opening and closed at its outer end except for a slit therein to function as a check valve, a tube connected to the pump and fitting in the sleeve to hold the sleeve in place in the opening and to supply air from the pump therethrough to the barrel, and a yieldable restriction at the forward end of the barrel to control the discharge of projectiles therefrom.

6 :4. A repeating .airguncomprising: arigid tubular barrel adapted to hold a series of -projectiles,.-a hollowistock :secured-to the rear; end .of the barrel, apumpcylinder in the stockto the rear of the barrel, a piston inthe cylinder, a pistorrrod connected to the-piston extending slidably through and guided by. the stock below the. barrel, a

handle secured to the forward end of the piston rod and underlying the barrel, a closure for the rear end of. the barrel'fonned with an opening therethrough, an elastic sleeve extending through theopening and closed at its outer end except for aslit therein to function as a check valve, atube connected to the pump and fitting in the sleeve .to hold: the sleeve. in place in-the opening-"andto .Supply air'from the pump therethrough to the barrel, and an elastic sleeve fitting over the outer end of the barrel projecting beyond the barrel and being restricted beyond the end of the barrel toengage and sealvagainst a projectile.

5. A repeatingair'g un comprising a rigid tubular barrel adapted to hold :a series of projectiles: which fit loosely in the barrel, a resilient restriction at the forward discharge endof the barrel to seal against the foremost projectileand to yield in response to a predetermined pres- .sure for discharge of the projectile, a pump to force air under pressure into the rear end of the barrel, and a tyielding ball of-air-pervious-material fitting slidably in the. barrel with a light friction fit to the rear of the proujectiles.

.6. A-repeating air 'gun comprising a rigid tubular barrel :adapted to hold projectiles which fit loosely in the barrel, a resilient sleeve fitting over theoutside of the barrel adjacent. the discharge end of the barrel and projecting 'sbeyond theydischarge -end of =the barrel,-means securing the sleeve to the barrel at a point spaced from the end of the barrel, the projecting portion of said sleeve being thicker than the adjacent portion and defining a restriction beyond the end of the barrel to engage and seal against a projectile, said adjacent portion of the sleeve between the secured portion and the projecting portion loosely overlying the barrel and being of a thickness such as to be expanded about the discharge end of the barrel in response to building up of air pressure behind a projectile in sealing engagement against the restriction, and means to force air under pressure into the barrel to move successive projectiles into sealing engagement with said restriction first to effect expansion of said adjacent portion of the sleeve about the discharge end of the barrel in response to sealing engagement of each projectile against the restriction and next to effect expansion of said restriction and ejection of the said projectile therethrough with resultant collapse of said adjacent portion.

7. A repeating air gun comprising a rigid tubular barrel adapted to hold projectiles which fit loosely in the barrel, a resilient sleeve fitting over the outside of the barrel adjacent the discharge end of the barrel and projecting beyond the discharge end of the barrel, means securing the sleeve to the barrel at a point spaced from the end of the barrel, the projecting portion of said sleeve being thicker than the adjacent portion and defining a restriction beyond the end of the barrel to engage and seal against a projectile, said adjacent portion of the sleeve between the secured portion and the projecting portion loosely overlying the barrel and being of a thickness such as to be expanded about the discharge end of the barrel in response to building up of air pressure behind a projectile in sealing engagement against the restriction, a follower fitting slidably in and frictionally engaging the barrel and formed for restricted flow of air therepast, and means to force air under pressure into the barrel to move successive projectiles into sealing engagement with said restriction first to effect expansion of said adjacent portion of the sleeve about the discharge end of the barrel in response to sealing engagement of each projectile against the restriction and next to effect expansion of said restricti'on and ejection of the f with resultant collapse of said adjacent portion.

said projectile therethrough 8. A repeating air gun comprising a rigid tubular barrel adapted to hold projectiles which fit loosely in the barrel, a resilient sleeve fitting over the outside of the barrel adjacent the discharge end of the barrel and projecting beyond the discharge end of the barrel, means securing the sleeve to the barrel at a point spaced from the end of the barrel, the projecting portion of said sleeve being thicker thanthe adjacent portion and defining a restriction beyond the end of the barrel to engage and seal against a projectile, the projecting portion of said sleeve being foldable over said adjacent portion and over the barrel for loading of projectiles through the discharge end of the barrel, said adjacent portion of the sleeve be- ,tween the secured portion and the projecting portion means to force air under pressure into the barrel to move successive projectiles into sealing engagement with said restriction first to eifect expansion of said adjacent portion of the sleeve about the discharge end of the barrel in response to scaling engagement of each projectile against the restriction and next to etiect expansion of said restriction and ejection of the said projectile therethrough with resultant collapse of said adjacent portion.

9. A repeating air gun comprising a rigid tubular barrel adapted to hold projectiles which fit loosely in the barrel, an annular external flange on the barrel spaced inwardly from its discharge end, a resilient sleeve comprising relatively thick end rings and an interconnecting thinner portion, said sleeve fitting over the outside of the barrel adjacent the discharge end of the barrel with one of the end rings engaging over the flange and the other projecting beyond the discharge end of the barrel, the projecting portion of said sleeve defining a restriction beyond the end of the barrel to engage and seal against a projectile, said thinner adjacent portion of the sleeve between the secured ring portion and the projecting ring portion loosely overlying the barrel and being of a thickness such as to be expanded about the discharge end of the barrel in response to building up of air pressure behind a projectile in sealing engagement against the restriction, and

means to force air under pressure into the barrel to move successive projectiles into sealing engagement with said restriction first to efiect expansion of said adjacent portion of the sleeve about the discharge end of the barrel in response to scaling engagement of each projectile against the restriction and next to efliect expansion of said restriction and ejection of the said projectile therethrough with resultant collapse of said adjacent portion.

References Cited in the file of this patent UNITED STATES PATENTS 2,273,678 Webby Feb. 17, 1942 2,375,607 Wulfert May 8, 1945 2,574,408 Moe Nov. 6, 1951 2,630,108 White Mar. 3, 1953 2,653,593 Foster Sept. 29, 1953 FOREIGN PATENTS 473,731 Canada May 22, 1951 

